1. Field of the Invention
This invention relates to a method for manufacturing mineral-fiberboard products typically of the type used for acoustical ceilings and is more particularly directed to a low density board having a damage-resistant dense surfacing layer.
2. Description of the Prior Art
The formation of fiberboard products having two or more layers of differing properties is known in the art and various techniques for achieving fiberboard products having surfacing layers which differ from the backing layer to which they are applied are exemplified by British Pat. No. 1,064,091, U.S. Pat. No. 1,996,343, U.S. Pat. No. Re. 27,109, and U.S. Pat. No. 3,513,009.